Preparation and evaluation of dual-mode floating gastroretentive tablets containing itraconazole

A novel Posaconazole oral formulation using spray dried solid dispersion technology: in-vitro and in-vivo study

SD (solid dispersion) technology is one of the well-recognized solubility enhancement methods; but the use of versatile carriers in ASD (amorphous SD) to achieve the added advantage of modified release along with solubility improvement is an emerging area of exploration. Spray drying is a widely used technology with excellent scalability and product attributes. The SD carriers explored were Soluplus®, possessing excellent solubilization properties that may enhance bioavailability and is suitable for innovative processing, and Gelucire 43/01, a lipid polymer utilized in a non-effervescent-based floating gastro-retentive DDS for the modified release of API. The CPPs of spray drying were screened during preliminary trials, and the formulation variables were optimized using a 32 Full Factorial Design. All nine batches were evaluated for % yield, % drug content, flow properties, floating behavior, saturation solubility, and in-vitro drug release in 0.1 N HCl. The optimized batch characterized based on DSC (differential scanning calorimetry) and PXRD (powder X-ray diffraction) confirmed the amorphous nature of entrapped drug in SDD (spray-dried dispersion). Particle size analysis and SEM (scanning electron microscopy) demonstrated micron size irregular shaped particles. Residual solvent analysis by GCMS-HS confirmed the elimination of organic solvents from SDD. The optimized batch was found stable after 6 months stability study as per ICH guidelines. In-vivo roentgenography study in New Zealand white rabbit showed the residence of SDD in gastric environment for sufficient time. The pharmacokinetic study was performed in male Sprague-Dawley rats to determine the bioavailability of developed SDD based product in fasting and fed conditions, and to compare the data with marketed Noxafil formulation. The current research is focused on the development of a novel ternary SDD (spray-dried dispersion)-based gastro-retentive formulation for an anti-fungal drug Posaconazole.

Polymeric Excipients in the Technology of Floating Drug Delivery Systems

The combination of targeted transport and improvement of the release profile of the active pharmaceutical ingredient (API) is a current trend in the development of oral medicinal products (MP). A well-known way to implement this concept is to obtain floating gastroretentive delivery systems that provide a long stay of the dosage form (DF) on the surface of the stomach contents. The nomenclature of excipients (Es) of a polymeric nature used in the technology of obtaining floating drug delivery systems (FDDS) is discussed. Based on the data presented in research papers, the most widely used groups of polymers, their properties, and their purpose in various technological approaches to achieving buoyancy have been determined. In addition, ways to modify the release of APIs in these systems and the Es used for this are described. The current trends in the use of polymers in the technology of floating dosage forms (FDF) and generalized conclusions about the prospects of this direction are outlined.

Evaluating the efficacy of slow-releasing carbon source tablets for in situ biological heterotrophic denitrification of groundwater

Slow-releasing precipitating tablets (SRPTs) and slow-releasing floating tablets (SRFTs) were formulated to release fumarate as a carbon source (CS) and/or electron donor (ED) in an in situ biological heterotrophic denitrification system. These tablets were prepared using pharmaceutical manufacturing. Soil column tests were conducted to evaluate nitrate denitrification efficacy, microbial population changes, and mass balance of fumarate and potential electron acceptors. Significant and simultaneous consumption of both fumarate and nitrate, and the production and consumption of nitrite were observed in both SRPT-treated and SRFT-treated soil columns. These results suggest that SRPT and SRFT releasing fumarate, induce heterotrophic biological denitrification. In the SRPT- and SRFT-treated columns, 65% and 73% of fumarate were associated with heterotrophic denitrification, respectively. Particularly, surplus citric acid, originally designed to serve as a floating agent, was utilized for 36% and 28% for SRFT flotation and denitrification, respectively. The results of 16s RNA analyses revealed that a bacterium that shared 99% 16s rRNA sequence similarity with those of Azoarcus sp. AN9, and Pseudogulbenkiania sp. NH8B, a facultative heterotrophic denitrifier, was detected in the column effluent. This study confirms that SRPT and SRFT can effectively operate long-term in situ biological denitrification processes, because it is possible to supply detailed CS and/or ED uniformly by applying both SRPT and SRFT in the well.

Production, characterization, and evaluation of two types of slow-releasing carbon source tablets for in-situ heterotrophic nitrate denitrification in aquifers

Slow-releasing carbon source tablets were manufactured for an in-situ biological denitrification system. The average zero-order nitrate degradation rates seen, from highest to lowest, were in microcosms to which lactate, fumarate, propionate, and formate had been added. Fumarate was approximately 80% cheaper than lactate, and consequently was determined to be the most optimal slow-releasing carbon source in tablet form. The slow-releasing precipitating tablet (SRPT) and slow-releasing floating tablet (SRFT) were manufactured with hydroxypropyl methylcellulose (HPMC) as the agent of release control, microcrystalline cellulose pH 101 (MCC 101) as the binder, #8 sand as the precipitation agent, and calcium carbonate and citric acid as floating agents. Fourier transform infrared spectroscopy and powder X-ray diffraction indicated that the crystal arrangement in the SRPTs and SRFTs was maintained and ordered in a manner similar to raw excipients. SRFTs floated in water within 30 min and remained so for 5 d due to the buoyancy of carbon dioxide. The carbon source release rate was proportional to the quantity of HPMC added. The longevities of SRPT with 300 mg of HPMC and SRFT with 400 mg of HPMC were 25.4 d and 37.3 d, respectively. This study observed that SRPT and SRFT were manufactured effectively and are suitable for in-situ slow-releasing biological systems.

Alfuzosin hydrochloride-loaded low-density gastroretentive sponges: development, in vitro characterization and gastroretentive monitoring in healthy volunteers via MRI

The current work aimed to develop low-density gastroretentive sponges loaded with alfuzosin HCl (ALF) to sustain the rate of drug release, improve its oral bioavailability and deliver it to the main site of absorption. Sponges were developed, according to a 2³ full factorial design, by compression of the lyophilized ALF-loaded hydroxypropylmethylcellulose (HPMC) or chitosan (CH) solutions. The influences of the polymer type, grade and concentration on the appearance, topography, porosity, density, in vitro ALF release, floating behavior, swelling, erosion, and mucoadhesive potential of the developed sponges were explored. Based on the desirability value, the best achieved system was selected. The gastroretentive potential of this system was evaluated in healthy male volunteers via MRI. Soft and flexible sponges were developed. They were characterized with interconnecting pores and channels and had excellent floating properties with respect to floating lag time and duration. Compared to HPMC-based sponges, CH-based ones exhibited higher porosity, larger pore diameters, lower bulk densities, higher drug release rates, larger swelling ratios, faster erosion rates and better mucoadhesive properties. MRI of magnetite-loaded best-achieved CH-based system (F8) ascertained the development of a promising gastroretentive system; exhibiting a gastric residence period of at least 5 h.

Preparation and evaluation of non-effervescent gastroretentive tablets containing pregabalin for once-daily administration and dose proportional pharmacokinetics

The main purpose of this study was to develop gastroretentive tablets with floating and swelling properties for once-daily administration of pregabalin. The non-effervescent floating and swelling tablets were prepared using wet granulation and compaction, which are widely used and easily accessible. All formulations showed sustained release patterns and maintained buoyancy for over 24 h. The amount of hydroxypropyl methylcellulose and crospovidone were found to be critical factors affecting in vitro dissolution and floating properties of the prepared tablets. The optimized tablets containing 300 mg of pregabalin started to float within 3 min and swelled above 12.8 mm, the reported pyloric sphincter diameter during the fed state, in all dimensions including length, width, and thickness. In vivo results in beagle dogs indicated that the optimized formulations are suitable as once-daily dosage forms, and dose proportionality was observed in doses ranging from 75 to 300 mg. Additionally, the dogs administered with the formulation having poor in vitro gastroretentive properties showed highly variable and reduced extent of absorption, signifying the necessity of the gastroretentive drug delivery system. In conclusion, the developed non-effervescent floating tablets are promising candidates for once-daily delivery of pregabalin.

Recent advances in delivery of antifungal agents for therapeutic management of candidiasis

Candidiasis is a fungal infection caused by yeasts that belong to the genus Candida. There are over twenty species of Candida yeasts that can cause infection in humans, the most common of which is Candida albicans. Candida yeasts normally reside in the intestinal tract and can be found on mucous membranes and skin without causing infection; however, overgrowth of these organisms can cause symptoms to develop. Presence of other diseases that compromises the patient's immunity makes it more difficult to treat. Candidiasis is majorly divided into superficial infections (oral or vaginal) and systemic infections, also known as invasive candidiasis. The conventional therapeutic modalities used to treat candidiasis are associated with several side effects that limits the dose and dosing frequency. Development of novel drug delivery systems for reduction in dose and alleviation of side effects is an important strategy to improve the clinical efficacy and patient acceptability. This review gives a bird's eye view of the classification and current therapeutic regime of candidiasis. It presents the varied types of drug delivery systems that have been exploited for delivery of antifungal agents with measurable benefits. It also touches upon echinocandins a relatively new class of drugs that are amenable for translation into novel dosage forms with application against biofilm producing and fluconazole resistant strains contributing to a better therapeutic management of candidiasis.

Release kinetics of highly porous floating tablets containing cilostazol

This study focuses on developing a highly porous floating tablet containing cilostazol. The underlying release mechanism of cilostazol from porous and floating tablets in dissolution media containing surfactants was investigated. The tablets were prepared by compressing granules and excipients with a sublimating agent, followed by sublimation under vacuum. The volatile material for the sublimating agent was chosen based on its flow properties using conventional methods as well as the twisted blade method. Resultant tablets could float immediately and had significantly higher tensile strengths than conventional tablets of similar porosities, holding a promising potential for increasing gastroretentive properties. Fitting the release profiles to the Korsmeyer-Peppas equation indicated Super Case II, Case II and non-Fickian kinetics, which implied that the release was affected by both floating behavior and matrix erosion. Abrupt changes in release kinetic parameters and erosional behaviors were found between the tablets containing different amounts of HPMC, indicating the existence of an excipient percolation threshold. Neither the surfactant in the media nor the porosity affected the dominant release mechanism, which was matrix erosion. Understanding the dominant release mechanism and percolation threshold allows for tuning the formulation to obtain various release profiles.